As their managerial search gains traction, the Washington Nationals have compiled a list of candidates that includes Los Angeles Dodgers bench coach Don Mattingly and former big league managers Bobby Valentine and Bob Melvin. Mattingly told reporters on Tuesday that he's been approached by the Nationals, who are interested in an interview. Sources both within and outside the organization confirmed the interest in Valentine and Melvin, though certainly the team's list goes deeper than three.

"I told [Nationals GM] Mike [Rizzo] to call me back after our season's over," said Dodgers General Manager Ned Colletti. "[Mattingly] is tremendously valued in our organization, both professionally and personally. I heard wonderful things about him, long before there was any chance of him becoming a Dodger. When we hired [Manager] Joe [Torre], I asked him how long he wanted to manage. He said probably three years. I said, fine, I would like to get someone you'd like to groom as a successor on your staff. And he said great, I have just the guy in mind. And it was Don."

The Nationals, coming off back-to-back 100-loss seasons, will also consider interim manager Jim Riggleman, whose guidance improved the team after he took over for Manny Acta during the all-star break. Riggleman, at home in Madeira Beach, Fla., so far has had no contact with the team's front office this offseason.

Team President Stan Kasten on Wednesday declined to comment on specifics of the team's managerial search, but did say a decision could come, at the latest, one week after the World Series ends.

"And that's only if there are people Mike [Rizzo] wants to talk to that are in the World Series," Kasten said. "But it could be any day."

He added that the organization preferred to conduct its search entirely in private, because "it's better for our organization. It's better for the people we're talking to. And also because we do have an incumbent manager as well. It's a ticklish time for our organization."

It remains unknown if the Nationals have conducted formal interviews with their candidates, but either way, the team appears to be a step behind other teams -- Houston and Cleveland -- with managerial openings. Mattingly, for instance, has already had a phone interview with Cleveland General Manager Mike Shapiro and assistant general manager Chris Antonetti. Mattingly said the Nationals are "on a different timetable" than the Indians.

Unlike Mattingly, who is a trusted lieutenant for Torre, Melvin and Valentine both have years of managerial experience. Melvin, with a .493 lifetime winning percentage, has managed the Seattle Mariners (2003-04) and the Arizona Diamondbacks (2005-09), where he was fired in midseason. Rizzo worked as Arizona's scouting director during the first 1 1/2 years of Melvin's tenure.

Valentine, for the moment, is working as an ESPN baseball analyst, but that could be a temporary position. Valentine is also a finalist for the Cleveland job, after managing in Japan for the last six seasons. Before that detour, Valentine managed the Texas Rangers (1985-92) and the New York Mets (1996-2002), taking the Mets twice to the playoffs and once to the World Series.

This is the second time the Nationals have had a managerial opening since their relocation to Washington. The previous time, in 2006, their search led to Acta, a first-time manager. During the search they also had intense interest in current Yankees manager Joe Girardi, who twice met with then-general manager Jim Bowden and then withdrew his name from consideration. Bowden used his Twitter account on Tuesday to write that Girardi was so close to becoming Washington's manager that the team stitched a uniform for him.

Staff writer Dave Sheinin contributed to this report from Philadelphia.